Infants require a specific amount of nutrients at specific times throughout the day. Often times such nutrients are delivered through formula. Formula is a powdered substance containing nutrients that is mixed with water to create liquid formula, which can then be fed to an infant.
There are times when mixing formula is inconvenient, such as outings away from home. Formula may be pre-mixed but it is typically recommended that pre-mixed formula be consumed within one hour of mixing, as the shelf life of mixed formula is about two hours. This can lead to wasted formula if the infant is not hungry within an hour of mixing.
Therefore, feeding formula either requires the transportation of powdered formula, water and a baby bottle separately, or the use of a device that stores baby formula into which water can be added to create formula. These devices are often expensive, complicated to manipulate, requiring finesse to use, and are difficult to clean.